General Hurricane Information

 Hurricanes are cyclones over water while tornadoes are cyclones over land. 

Hurricane season runs from June 1 to November 30 each year. September is the highest probability month of the season. There is an average of 10 named storms per season according to the National Hurricane Center. A storm gets named as it reaches tropical storm status. Residents and visitors to the area should learn the elevation of where they are in relation to sea level and the storm surge history of the area. Storm surge is a dome-like rise in the ocean level associated with the hurricane. 

Meteorologists classify hurricanes by categories of 1-5 using a scale that measures the wind and speed of the storm. A Tropical Depression has a highest wind speed of 38 miles per hour (33 knots), with some rotary circulation and one or more closed isobars. A Tropical Storm has distinct rotary circulation with wind speeds of 39- 73 miles per hour (34-63 knots), closed isobars and a pressure of 14.0 pounds per square foot. A Hurricane has strong and very pronounced rotary circulation, closed isobars, a pressure of 17 or more pounds per square foot and winds of 74 miles per hour (64 knots) and higher. The devastating class 5 hurricane exceeds wind speed of 156 miles per hour.

The Forecasted 2011 Atlantic Season

The Atlantic basin is expected to see an above-normal hurricane season this year, according to the seasonal outlook issued by NOAA's Climate Prediction Center - a division of the National Weather Service. NOAA's 2011 Atlantic Hurricane Season Outlook calls for a 65% chance of an above normal season. The outlook indicates only a 25% chance of a near-normal season and a 10% chance of a below-normal season.
 

(Image courtesy of NOAA)

An important measure of the total overall seasonal activity is the NOAA Accumulated Cyclone Energy (ACE) index, which accounts for the intensity and duration of named storms and hurricanes during the season. We estimate a 70% chance that the 2011 seasonal ACE range will be 105%-200% of the median. According to NOAA's hurricane season classifications, an ACE value above 117% of the 1950-2000 median reflects an above-normal season. An ACE value above 175% of the median reflects an exceptionally active (or hyperactive) season.

Consistent with the expected ACE range, the 2011 Atlantic hurricane season is expected (with 70% chance) to produce 12-18 named storms, 6-10 hurricanes, and 3-6 major hurricanes. Each of these ranges indicate that activity will exceed the seasonal average of 11 named storms, six hurricanes, and two major hurricanes. Therefore, this season could see activity comparable to a number of extremely active seasons since 1995.

2011 Tropical Cyclone Names (Atlantic)

For more information:
Florida Hurricane Info
NOAA
FEMA
Center for Disease Control - CDC